The invention is in the field of conveying technology and relates to a method for conveying individually held products according to the preamble of the first independent claim, as well as to an arrangement for performing the method according to the preamble of the corresponding independent claim.
The products to be considered hereinafter are held individually and are conveyed substantially continuously through a network of conveying paths on optionally individual routes. By this conveying operation the products are e.g. brought from a manufacturing process to stations in which they are individually further processed, or they are conveyed from one processing station to another or through processing stations in which they are processed during continuous conveyance. An example for products to be handled in this way are printed products which, coming from the printing press, are further processed and rendered ready for dispatch by the most varied processing stations.
It is known to individually convey printed products, in that each of the products is held by a gripper or some other suitable holding means. For this purpose e.g. a plurality of grippers or holding means are fixed to a transport chain and the chain is driven and guided in such a way that the products held by the grippers or holding means are conveyed in a predetermined manner over a predetermined conveying path. At points where all or individual products of such a product stream are to be passed from a first to a second conveying path, the two conveying paths are arranged relative to one another in such a way that the products can be taken over by the holding means of the second conveying path and can be released by the holding means of the first conveying path, normally without interruption of the continuous conveyance. For such operation, at the transfer point, control means are provided for both the participating conveying paths, the control means controlling activation of all or individual ones of the holding means (bringing them into a holding configuration) or deactivation (bringing them from the holding configuration into a non-holding configuration).
Also known are arrangements in which the holding means being movable along a conveying path are interconnected such that the spacings between them are variable. In the same manner as described above, transfer points of such arrangements are equipped with control means for activating or deactivating the holding means and such arrangements additionally comprise means for synchronizing the releasing and the taking-over holding means.
The above-described arrangements for conveying articles are particularly suitable for product streams, which are conveyed over longer conveying paths with a substantially unchanged product sequence. The arrangements are robust and easily operable even for very high conveying capacities and it is possible to implement the return of the holding means on a simple return path without any specific control.
However, if the products to be conveyed are easily mechanically damaged and have only a limited inherent stability, complicated guidance means have to be provided at the transfer points to ensure that the products are not damaged on being transferred and it is important to very precisely synchronize the movements of releasing holding means and of the taking-over holding means at the transfer point. Thereby, the guidance means and the synchronization must be adapted to each product type to be conveyed (product format). For there reasons conveying systems of this type are advantageously designed with a minimum number of transfer points.
Conveying systems comprising independent, i.e. non-interconnected holding means which are movable along conveying paths are known also. Such arrangements are particularly suitable for conveying methods with product-specific conveying routes whereby for guiding the movement of the holding means guidance systems with branching points and return points are provided, the switch points being controllable in a product-dependent manner. Such conveying systems can be operated in a very flexible manner, but tend to be complicated regarding control and driving means. Controllable guidance systems must also be provided for the return of the holding means.
The object of the invention is to provide a method for conveying individually held products whereby the method is to combine the advantages of the above-described systems, but largely eliminating their disadvantages. In particular, the method is to be substantially independent of shape variations with respect to the products to be conveyed. The method is to be usable for very high conveying capacities and is to be better adaptable than known methods of the same type to the most varied conveying functions in different areas through which the products are to be conveyed. A further object of the invention is to provide an arrangement for carrying out the method, said arrangement being easily adaptable to the most varied, local conveying functions and also easily extendable.
This object is achieved by the method and the arrangement, as defined in the claims.
The inventive method is based on associating a holding element with each product to be conveyed, the holding element holding the product in a clearly defined manner and covering together with the product the entire conveying route intended for the product, said route comprising a series of conveying paths. For conveying, the holding elements are coupled to parts movable along a specific conveying path or to guides extending along a specific conveying path.
A network of clearly defined conveying paths is provided, together with a plurality of holding elements. Each of the holding elements has at least one first coupling part, with the aid of which it can be coupled to a second coupling part, each second coupling part being associated with a specific conveying path and being movable along this path. According to another method variant, the holding elements are coupled to guides extending along a conveying path with the aid of the first coupling parts.
For conveying it along a conveying path, a product is held by a holding element and the holding element is coupled to a second coupling part with the aid of the first coupling part, the second coupling part being movable along the conveying path. It is possible also to couple the holding element with the aid of the first coupling part to a guide extending along the conveying path. The coupling part, the conveying element on which the coupling part is located, or the holding element is driven along the conveying path by suitable means. In transfer areas, i.e. at points where the product is passed from one conveying path to another conveying path, the holding element is uncoupled from the second coupling part movable on the first conveying path or from the corresponding guide and it is coupled to a second coupling part movable on the second conveying path or to a corresponding guide, thereby of a stream of products either all products are transferred or specific products only.
The advantage of the inventive method is the fact that the products to be conveyed have to be gripped or grasped only once. This significantly reduces the damage risk and renders the method substantially independent of the precise product shape. In addition, the second coupling parts movable on the conveying paths are movable in very different ways depending on the conveying function of a specific conveying path within a given network of conveying paths. The second coupling parts can e.g. be arranged equidistantly on conveying chains. If holding elements are coupled to such a conveying chain, their function corresponds to a known conveying chain of the type described hereinbefore. The second coupling parts can also be positioned on links of chains having variable link spacings or they can be arranged on completely independently movable conveying elements. Corresponding drive means can be designed and positioned depending on the nature of the movement of the second coupling parts along a specific conveying path.
In addition to the conveying paths with second coupling parts movable thereon, in an arrangement according to the invention there may also be conveying paths on which the holding elements can be moved without coupling, e.g. in that their first coupling parts slide in correspondingly designed guides, e.g. being driven by the force of gravity. Such additional conveying paths are particularly suitable for non-continuous conveying, e.g. for buffer paths and return paths.
A further advantage of the method and arrangement according to the invention is the fact that in processes in which it is advantageous to individually identify the products, suitable identification means do not have to be located on the actual products, but instead can be carried by the holding elements and therefore, do not leave the conveying system. Such identification means are e.g. electronic units which are writable and readable without contact.